/******************************************************************
 *
 * Copyright 2018 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ******************************************************************/

/****************************************************************************
 *
 *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <sched.h>
#include <assert.h>
#include <debug.h>

#include <tinyara/arch.h>
#ifdef CONFIG_TLS
#include <tinyara/tls.h>
#endif
#include <tinyara/board.h>

#include "xtensa.h"
#include "sched/sched.h"

#ifdef CONFIG_STACK_COLORATION

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static size_t do_stackcheck(uintptr_t alloc, size_t size);

/****************************************************************************
 * Name: do_stackcheck
 *
 * Description:
 *   Determine (approximately) how much stack has been used be searching the
 *   stack memory for a high water mark.  That is, the deepest level of the
 *   stack that clobbered some recognizable marker in the stack memory.
 *
 * Input Parameters:
 *   alloc - Allocation base address of the stack
 *   size - The size of the stack in bytes
 *
 * Returned Value:
 *   The estimated amount of stack space used.
 *
 ****************************************************************************/

static size_t do_stackcheck(uintptr_t alloc, size_t size)
{
	FAR uintptr_t start;
	FAR uintptr_t end;
	FAR uint32_t *ptr;
	size_t mark;

	if (size == 0) {
		return 0;
	}

	/* Get aligned addresses of the top and bottom of the stack */

#ifdef CONFIG_TLS
	/* Skip over the TLS data structure at the bottom of the stack */

	DEBUGASSERT((alloc & TLS_STACK_MASK) == 0);
	start = alloc + sizeof(struct tls_info_s);
#else
	start = alloc & ~3;
#endif
	end = (alloc + size + 3) & ~3;

	/* Get the adjusted size based on the top and bottom of the stack */

	size = end - start;

	/* The Xtensa CPUs use a push-down stack:  the stack grows toward lower
	 * addresses in memory.  We need to start at the lowest address in the
	 * stack memory allocation and search to higher addresses.  The first word
	 * we encounter that does not have the magic value is the high water mark.
	 */

	for (ptr = (FAR uint32_t *)start, mark = (size >> 2); *ptr == STACK_COLOR && mark > 0; ptr++, mark--) ;

	/* If the stack is completely used, then this might mean that the stack
	 * overflowed from above (meaning that the stack is too small), or may
	 * have been overwritten from below meaning that some other stack or data
	 * structure overflowed.
	 *
	 * If you see returned values saying that the entire stack is being used
	 * then enable the following logic to see it there are unused areas in the
	 * middle of the stack.
	 */
	
	/* Return our guess about how much stack space was used */

	return mark << 2;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_check_stack and friends
 *
 * Description:
 *   Determine (approximately) how much stack has been used be searching the
 *   stack memory for a high water mark.  That is, the deepest level of the
 *   stack that clobbered some recognizable marker in the stack memory.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   The estimated amount of stack space used.
 *
 ****************************************************************************/

size_t up_check_tcbstack(FAR struct tcb_s *tcb)
{
	return do_stackcheck((uintptr_t)tcb->stack_alloc_ptr, tcb->adj_stack_size);
}

ssize_t up_check_tcbstack_remain(FAR struct tcb_s *tcb)
{
	return (ssize_t)tcb->adj_stack_size - (ssize_t)up_check_tcbstack(tcb);
}

size_t up_check_stack(void)
{
	return up_check_tcbstack(this_task());
}

ssize_t up_check_stack_remain(void)
{
	return up_check_tcbstack_remain(this_task());
}

#if CONFIG_ARCH_INTERRUPTSTACK > 3
size_t up_check_intstack(void)
{
	return do_stackcheck((uintptr_t)&g_intstackalloc, (CONFIG_ARCH_INTERRUPTSTACK & ~3));
}

size_t up_check_intstack_remain(void)
{
	return (CONFIG_ARCH_INTERRUPTSTACK & ~3) - up_check_intstack();
}
#endif

#endif							/* CONFIG_STACK_COLORATION */
